A new paper has been accepted for publication and is now online on the Journal of Chemical Physics website [J. Chem. Phys. 134, 164102 (2011) ]. The article “A natural orbital functional for multiconfigurational states” by M. Piris, X. Lopez, F. Ruipérez, J. M. Matxain and J. M. Ugalde can now be accesed ﻿at doi:10.1063/1.3582792